Magnesium Ascorbyl Phosphate: A Stable Form Of Vitamin C Is It Really As Good As Other Vitamin C Ingredients?



What Is Magnesium Ascorbyl Phosphate?

Magnesium ascorbyl phosphate is a form of vitamin C that is used in skincare products for its ability to protect the skin from free radicals, stimulate collagen production, reduce hyperpigmentation, and maintain skin hydration. 

Magnesium ascorbyl phosphate, like all the different forms of vitamin C is converted in the body to L-ascorbic acid. L-ascorbic acid or vitamin C is the form that the body is able to utilise. 

Vitamin C is a naturally occurring antioxidant that is synthesized by most plants and animals from glucose. Humans lack the enzyme required for the synthesis of vitamin C, which means it must be acquired from dietary sources such as citrus fruits, green leafy vegetables, strawberries, papaya, and broccoli. 

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Vitamin C is necessary for the normal growth, development, and repair of damaged tissues in the body, as well as the enzymatic production of certain neurotransmitters. It is also important for immune system function.

After oral intake of vitamin C, the absorption in the gut is limited by an active transport mechanism. This means that no matter how much vitamin C you ingest only a finite amount can be absorbed. Further, the bioavailability of vitamin C in the skin is inadequate when it is administered orally. Therefore, the use of topical vitamin C is important to reap all of the skin benefits that vitamin C has to offer.

Vitamin C exists in many different forms, including tetrahexyldecyl ascorbate, ascorbyl palmitate, mineral ascorbates, calcium ascorbate and magnesium ascorbyl phosphate. 

Magnesium ascorbyl phosphate is considered to be a stable and effective antioxidant for the skin and usually comes in concentrations around 5%. It has a neutral or skin neutral pH which makes it easy to formulate with and reduces the likelihood of sensitivity and irritation.

The most biologically active form of vitamin C, however, is L-ascorbic acid. While L-ascorbic acid can be used in topical products, its use is limited because it is unstable and causes the most skin irritation out of all the forms of vitamin C.

Magnesium Ascorbyl Phosphate

the good: is a stable and less irritating form of vitamin C which may help to improve the appearance of hyperpigmentation, minimize the signs of aging, and support collagen production.

the not so good: The main concern here is that magnesium ascorbyl phosphate doesn’t convert readily to L-ascorbic acid or vitamin C in the body. This limits its benefits to the skin.

Who is it for? All skin types except those that have an identified allergy to it.

Synergetic ingredients: Works well with most ingredients

Keep an eye on: Keep an eye out for which vitamin C ingredient is used in your product.

What Are The Benefits of Magnesium Ascorbyl Phosphate?



One advantage of magnesium ascorbyl phosphate is that it provides a stable, water-soluble form of vitamin C.

Unlike L-ascorbic acid, it does not readily degrade in formulas containing water. It is also considered light-stable and oxygen-stable. Studies of magnesium ascorbyl phosphate in aqueous solutions indicate it retains over 95% of its potency at 40°C without any pH adjustment. 

Furthermore, at a pH of 7, magnesium ascorbyl phosphate is easily absorbed into the skin and is less likely to cause irritation than ascorbic acid.



Magnesium ascorbyl phosphate functions as an antioxidant. Like other antioxidants, it is capable of protecting the skin from free radicals. Specifically, magnesium ascorbyl phosphate donates electrons to neutralize free radicals such as the superoxide ion and peroxide that are generated when the skin is exposed to UV light. 

This is important because the harmful effects of free radicals occur as damage to  the cellular DNA, the cell membrane, and the cellular proteins, including collagen. 

Damaged collagen may manifest as signs of premature aging of the skin, including wrinkles, lines, and sagging skin. Therefore, the ability of magnesium ascorbyl phosphate to protect collagen within the skin makes it an ideal ingredient to include in anti-aging skincare products.



L-ascorbic acid, interacts with copper ions at tyrosinase-active sites and inhibits the action of the enzyme tyrosinase, the main enzyme responsible for the conversion of tyrosine into melanin, thereby decreasing melanin formation. 

In simpler terms, It reduces the uneven distribution of melanin pigment or the molecule responsible for creating color in the skin. By decreasing the synthesis of melanin, the appearance of dark spots is reduced.



Magnesium ascorbyl phosphate is also studied for its potential hydrating effect on the skin and its ability to limit transepidermal water loss. Transepidermal water loss or TEWL refers to water being loss from the skin to the air. This occurs in dry environments and increases as we age. TEWL is also closely linked with the health of your skin’s natural barrier. 

Keeping skin hydrated is vital to prevent signs of aging. When your skin becomes dehydrated, symptoms of dryness, flakiness, roughness, irritation, and cracking appear; hence the look of prematurely aged skin. 

Furthermore, dehydrated skin is less effective as a protective barrier, which means your skin tends to react easily to active ingredients or external elements. This is known as sensitive skin. By keeping the skin hydrated, magnesium ascorbyl phosphate may help to prevent these symptoms.

Does Ascorbyl Palmitate Work As Well As Other Vitamin C Ingredients?

The type of vitamin C often varies  between formulations. As a vitamin C source, L-ascorbic acid is the most well-researched source and the source that has shown the most benefits to the body. 

Other forms of synthetic vitamin C used in skincare, such as ascorbyl palmitate, mineral ascorbates, calcium ascorbate, magnesium ascorbate,or tetrahexyldecyl ascorbate can have a significant effect on the efficacy of the product.

Studies have shown that most vitamin C products that don’t use L-ascorbic acid tend to be less potent and less well aborbed into the skin. 

However there has been some research to suggest that magnesium ascorbyl phosphate may be useful in supporting collagen production under lab test conditions. This may be promising however, more reserach is needed to determine how effective it is as compare to L-ascorbic acid. 

Is Magnesium Ascorbyl Phosphate Vegan?

Magnesium ascorbyl phosphate is a vegan ingredient. It is derived from ascorbic acid and a magnesium salt which are mixed with a phosphorylating ingredient. All of these ingredients are vegan. 

However, it can also be made from animal-based products. For this reason it is always best to check with the brand that you intend on purchasing if their source is vegan. 

Is Magnesium Ascorbyl Phosphate Safe?

The safety of magnesium ascorbyl phosphate has been assessed by the Cosmetic Ingredient Review Expert Panel,  a group responsible for the independent evaluation of the safety and efficacfy of skincare and cosmetic ingredients.

The Expert Panel reviewed the available scientific data and concluded that this ingredient was safe for use in cosmetic and personal care products.

What Should You Consider When Choosing A Vitamin C Product?


Stability of your vitamin C product

L-ascorbic acid is a highly unstable molecule. It requires a water-based environment, a low pH and antioxidants to increase its ability to deeply penetrate the skin. Those conditions are important for creating a stable and active vitamin C product. It is essential to understand why L-ascorbic acid requires these conditions when choosing a vitamin C product in order to find one that is effective and long lasting. 

L-ascorbic acid has a reduced ability to penetrate the skin at its natural pH which is a result of its molecule structure. L-ascorbic acid is a charged molecule and is hydrophilic. These two characteristics mean that L-ascorbic acid will readily bind to water molecules, making it hard for the molecule to pass through the skin’s hydrophobic layers. 

Reducing the pH of a product to less than 3.5 or less makes it more acidic, allowing for L-ascorbic acid to penetrate deeper and be stable for longer.  However, reducing the pH of the product may lead to sensitization of the skin, as the natural pH of the skin is around 4.75-5.5. 

To create a more stable product that lasts longer, some formulations use different forms of vitamin C. This includes magnesium ascorbyl phosphate or ascorbyl-6-palmitate, which  are more stable at a neutral pH. However, a study conducted by Duke University Medical Center found that these two substitutes did not increase the natural vitamin C levels in the skin.

Some formulations include other antioxidants to help stabilize the L-ascorbic acid. Studies have suggested that incorporating ferulic acid and vitamin E can increase the stability and improve the product’s ability to penetrate deeply into the skin. A study published in the Journal for Investigative Dermatology found that ferulic acid stabilized the formulation and increased the protective capabilities of vitamin C to the sun’s effects.

In poorly designed products or formulations, the L-ascorbic acid can destabilize in the bottle, often leaving the product with a yellow hue. Oxidation is the process that causes this discoloration. In poorly designed formulations, the oxidation can also occur on the skin’s surface, leaving the skin with a buildup of free radicals and acidic by-products or waste. This can affect the health of the skin mantle barrier, interact with other products and hasten the aging process. 

L-ascorbic acid will only stay active in skincare products for a short period once opened. Even well-designed products will experience this, as exposure to the air will oxidize the L-ascorbic acid.  To increase a product’s longevity, look for powder formulations, products in vial form, or small product sizes. Look for products formulated with antioxidants such as ferulic acid. 



Concentration is another critical element when considering which L-ascorbic acid products would best suit your needs. Some brands advertise a high level of vitamin C in their product, such as 100% L-ascorbic acid. While it may seem appealing to have concentrated products, formulas with more than 20%  L-ascorbic acid can irritate the skin. Most dermatological studies have found that a range between 8-20% produces the best results with limited irritation. 

A study conducted by Duke University Medical Center found that the concentrations of L-ascorbic acid above 20% do not have increased skin benefits. The study determined that conversely, higher levels can negatively impact the skin’s condition. Sensitive skin types should use vitamin C products in the lower part of the range.


Synthetic or plant-based vitamin C

Occasionally brands won’t advertise the strength of the vitamin C content in the product but instead focus on the source. This lack of information regarding concentration tends to occur with formulations utilizing kakadu plum, hibiscus or plant-based vitamin C sources. The issue with plant-based sources of vitamin C is that they tend to be low in concentration and are generally unstable. The strength of L-ascorbic acid in kakadu plum is about 2% which means it cannot affect the skin in any significant way. The low concentration of L-ascorbic acid in plant-based sources and the instability of most natural sources is why most effective vitamin C products use a synthetic form of L-ascorbic acid in their formulations, including most clean beauty brands. 


Vitamin C products

Many product types can deliver vitamin C to the skin, including gels, serums and powders and oils in the case of a few derivatives.

L-ascorbic acid is a water-soluble molecule that requires a low pH and the inclusion of stabilizers and antioxidants, which means that most L-ascorbic acid formulations will be in a water base or dried form. Some are formulated in an oil base.

L-ascorbic acid delivered in gel or serums is absorbed quickly without adding extra moisturizing products which makes them suitable for oily or acne prone skin. They also work well with an established skincare routine, as they avoid disrupting a working regime. 

Powder forms of L-ascorbic acid prevent the need for many stabilizers. They reduce the risk of decreased effectiveness through exposure to the sun and air as the product becomes active only when mixed with water.


Other types of vitamin C

The type of vitamin C often varies between formulations. As a vitamin C source, L-ascorbic acid is the most well-researched source and the source that has shown the most benefits to the body. Other forms of synthetic vitamin C used in skincare are mineral ascorbates, calcium ascorbate, magnesium ascorbate, ascorbyl palmitate or tetrahexyldecyl ascorbate.  The type of vitamin C and the type of product can have a significant effect on the efficacy of the product.

Studies have indicated that tetrahexyldecyl ascorbate might equal L-ascorbic acid in terms of effectiveness. Tetrahexyldecyl ascorbate is an oil-soluble form of vitamin C that works alongside other products such as retinol. In a review conducted by the Cosmetic Ingredient Review, evidence indicated that tetrahexyldecyl ascorbate is more stable in solution, less irritating and able to penetrate deeper into the skin, making it a promising vitamin C treatment. 

Al-Niaimi F, Chiang NYZ. Topical Vitamin C and the Skin: Mechanisms of Action and Clinical Applications. J Clin Aesthet Dermatol. 2017;10(7):14-17.
Telang PS. Vitamin C in dermatology. Indian Dermatol Online J. 2013;4(2):143-146.



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